Car AC not working, garage topped up, lasted 1 day only!!

[Burnerman]

On the earlier systems, when you turned the A/C on you'd hear a clunk as the compressor clutch engaged and the revs would drop a fraction - not sure if that's applicable these days.
I have to say, I don't have A/C issues but I don't keep my cars too long - although the current scenario may change that.....Yonder Yeti will only do 2k miles this year but the Bipper makes up for it.
John

 

[Avocet]

Some still work like that (a sort of "tick" noise as the electromagnetic clutch on the compressor kicks in. However, some use smart-arsed variable displacement pumps now, where the pump always runs, but can make itself work harder or less hard as required.